Ningbo-Zhoushan port has started to turn ships away this morning in the wake of the positive nucleic test. The man resides in a dormitory and tested negative on August 8, before being retested on August 10.

A first, the port authority said that its operating system was down early this morning before the Ningbo Municipal Health Commission made a statement. The infected man was part of the workforce at Ningbo Meidong Container Terminal.

An unprecedented number of tankers, bulk carriers and containerships had by then backing up outside Ningbo-Zhoushan port.

Ningbo-Zhoushan handled 1.17 billion tons in 2020 making it the largest port in the world by some distance. Its annual box throughput is approaching 30 million, making it the third largest container port in the world.

When a Covid-19 outbreak was detected at Yantian Port in late May, operations at the key southern Chinese export hub were slashed by 70 per cent for most of June.

Since July 20, community-spread infections have been confirmed in roughly half of China's provinces, sparking mass testing operations and localised lockdowns.

Newly reported positive Covid-19 cases in China have recently forced the country to re-introduce restrictions to curb the spread of the virus.

Most ports in the country are now requiring a nucleic acid test (NAT) for all crew, with vessels forced to remain at anchor until negative results are confirmed.

Many ports in the country also require vessels to quarantine for 14-28 days if they previously berthed in India or performed a crew change within 14 days of arriving in China.